Test Driven DevelopmentTools and techniques

Talk overview• From idea to requirements, to development, to

deployment  Topics • Stories to Acceptance Tests• Unit Testing • Integration testing• Deployment testing

What is testing...Verification • Are we building

the software right?   Phases • Unit, Integration,

System, User Acceptance, Deployment

Validation • Are we building

the right software ?

   Phases • User Acceptance

Test or ALL?

What is testing...Verification • Are we building the

software right? 

Engineering focused

  Tools• MbUnit, Watin,

RhinoMocks, FXCop, NDepend, NCover...

 

 

Validation • Are we building

the right software ?

  Analysis focused

  

Tools• Fitnesse, Story

Teller, xBehave...

Classic developmentQuality is a side effect of the process not the driver of the process. • Developers, Business Analysts, Testers

throw requirements, code and bug reports over the wall

• No shared quality/testing strategyoDifferent groups use different tools

and techniques • Often manual• Regression tests labour/time intensive

Test Driven DevelopmentThe day to day philosophy Red, Green, GreenRed - Analysis/Design Hat• Create a test that defines the expected outcome• Asking "What I want is..."Green - Creative Hat (Fun part)• Experiment/Prototype/Build until the test passesGreen - Engineering• Refactor, refactor, refactor

Testing Dimensions

Modern TDDVerification and Validation performed continually, during all phases with everyone involved.  

• xUnit/CI is only the start• TDD mindset is pushing the boundaries of where

tests can become automated• New focus on down stream testing during

Requirements gathering • Breaking project into Stories promotes detailed

requirements over classical analysis which promotes "sweeping open ended statements"

Requirements

Precise and clear over verbose

We want requirements that  • Can be tested!!!

• Are attainable!!! 

• Can be easily mapped to User Stories!!!

• Are traceable into code!!!

Acceptance Tests

Using Fitnesse to Verify & ValidateFitNesse enables customers, testers, and programmers to learn what their software should do, and to automatically compare that to what it actually does do. It compares customers' expectations to actual results.  

http://fitnesse.org/FitNesse.OneMinuteDescription

 

FitnesseWhat is it?

• A wiki for writing acceptance tests

• Allows Text, Images and Test case data to be intermingled on the same page

• Promotes shared terminology between analysis and development (Ubiquitous language)

Its almost Christmas... 

Midland Organic Foods are thinking about Easter - Jack Plays Snap

• Jack climbs beanstalk when correctly snapping

• Jack wins when he reaches the top of the Beanstalk

• Giant snaps when Jack takes too long

 Fitnesse Demo

FitnesseDemo code was horrible...

• No transactions

• Not N-Tiered

• Inadequate error handling

• Prototype...

Fitnesse

As code is productioised

• Fixtures are updated • Wiki pages ARE NOT TOUCHED!!• Fixtures are a bridge between analysis and

implementationoComplex fixture implies translation of

ideasoStrive for Ubiquitious language...oRefactor, refactor, refactor...

Unit Testing

What is Unit Testing

• Testing individual units of code • Take smallest piece of testable

software in the application & isolate it from the remainder of the code

 • Simple, Repeatable, Fast

Advantages \ Disadvantages

•  Client & Developer confidence

 • Refactoring • Self documenting

•  Have to write more codeoBut..is this

REALLY a disadvantage?

Tools•  Testing frameworks

o MBUnit, NUnit, xUnit...many more • Test runners

o Testdriven.Net, Resharper, Gallio, TeamCity • Mocking

o RhinoMocks, NMock, Typemock • Code Coverage

o NCover

Unit Test Syntax

•  Arrange • Act • Assert

Example        [Test]        public void FindByName_Returns_FarmyardAnimal_When_In_Collection()  {

            //Arrange            string Animal_Name = "test";            FarmYardAnimal testAnimal = new FarmYardAnimal                                                                   {Name = Animal_Name};            FarmYardAnimals farmYardAnimals = new FarmYardAnimals();            farmYardAnimals.Add(testAnimal);

            //Act            FarmYardAnimal foundAnimal

=  farmYardAnimals.FindByName(Animal_Name);                //Assert            Assert.AreEqual(testAnimal,foundAnimal);        }

Mocking

•  Simulating objects that mimic the behavior of real objects in controlled ways.

 •  Isolate dependancies •  Only used in UNIT testing

Mocking cont...•  RhinoMocks

o  currently version 3.5o  written by Ayendeo  well maintainedo  lots of exampleso  can mock 

everything on interfaces or virtuals on classes

Mocking cont...•  Stubs

o  Supply the SUT with data 

o  No constraints 

o  Assert on SUT  •  Mocks

o  For interaction testing 

o  "Record" actions on the mock 

o  Assert on Mock using constraints

Stubbing - What we’re testing public bool GameFinished

{

get

{

return

(Beanstalk.AtTop ||

(Jack.Cards.Count == 0 && Giant.Cards.Count == 0));

}

}

Example of Stubbing[Test] public void GameFinished_True_When_BeanstalkAtTop_And_Neither_Jack_Or_Giant_HaveCards(){  //Arrange Queue<IPlayingCard> noCards = new Queue<IPlayingCard>();  IBeanstalk stubBeanstalk = MockRepository.GenerateStub<IBeanstalk>(); stubBeanstalk.Expect(sb => sb.AtTop).Return(true);

IPlayer stubJack = MockRepository.GenerateStub<IPlayer>(); IPlayer stubGiant = MockRepository.GenerateStub<IPlayer>(); stubJack.Expect(j => j.Cards).Return(noCards); stubGiant.Expect(j => j.Cards).Return(noCards);

Game gameToTest = new Game(stubJack , stubGiant , stubBeanstalk );  //Act bool isFinished = gameToTest.GameFinished;

//Assert Assert.IsTrue(isFinished);}

Mocking - What we're testing

public void Save(IGame game){            var status = new GameStatus                             {                                 Giant = game.Giant.Name,                                 Jack = game.Jack.Name,                                 CanSnap = game.CanSnap,                                 IsFinished = game.GameFinished,                                 ActivePlayer = game.ActivePlayer.Name                             };            try            {                _session.SaveOrUpdate(status);            }            catch (Exception ex){                throw new GameRepositoryException("Game Save Error", ex);

            }}

Example of Mocking cont..

[Test] public void GameRepository_Should_Convert_GameToGameStatus_And_Use_Session_To_Save(){ //Arrange GameStatus expectedStatus = new GameStatus{                        ActivePlayer = "active",CanSnap = true,                        Giant = "giant",Jack = "jack",IsFinished = false};   //Dont use stubs if creating the object directly is easier IPlayer jack = new Player(expectedStatus.Jack); IPlayer giant = new Player(expectedStatus.Giant); IPlayer activePlayer = new Player(expectedStatus.ActivePlayer);

//Create Game stub IGame stubGame = MockRepository.GenerateStub<IGame>(); stubbedGame.Expect(g => g.Giant).Return(giant); stubbedGame.Expect(g => g.Jack).Return(jack); stubbedGame.Expect(g => g.ActivePlayer).Return(activePlayer); stubbedGame.Expect(g => g.CanSnap).Return(expectedStatus.CanSnap); stubbedGame.Expect(g => g.GameFinished).Return(expectedStatus.IsFinished);

Example of Mocking....cont //create mock ISession mockedSession = MockRepository.GenerateMock<ISession>();

GameRepository repository = new GameRepository(mockedSession);  //Act repository.Save(stubGame);

//Assert mockedSession.AssertWasCalled(ms => ms.SaveOrUpdate(null),                                          options => options.Constraints(Property.AllPropertiesMatch(expectedStatus));

}

Constraints• Iso  Is.Null(), Is.NotNull(), Is.GreaterThan() etc

• Property oValue(“Status”,Status.Valid),

       IsNotNull(“User”), IsNull(“User”) etc • List

o constraints on lists e.g List.Count(2) • Text

o constraints on text e.g Text.StartsWith(“foo”)• Many more...  

Exception Path TestingstubbedSession         .Expect(s => s.SaveOrUpdate(null))         .IgnoreArguments()         .Throw(new Exception());

var gameRepository = new GameRepository(stubbedSession);

//Acttry{       gameRepository.Save(stubbedGame);}catch(GameRepositoryException exception){     //Assert }

State vs Interaction Testing

• Arrange and Act • Verify state of SUT as expected

 •  Uses only Stubs

• Arrange and Act • Verify SUT has interacted

with dependancy correctly • Can use Stubs & Mocks

MbUnit 

•  Testing framework • Currently at version 3 • Bundled with Gallio

  

Row Attribute[Test][Row("name1", "name2")][Row("name1", "name1", ExpectedException = typeof (ArgumentOutOfRangeException))]

public void Can_Only_Add_Animals_With_Unique_Names_To_FarmyardAnimals(string firstAnimalName,string secondAnimalName){//ArrangeFarmYardAnimals animals = new FarmYardAnimals();

//Actanimals.Add(new FarmYardAnimal {Name = firstAnimalName});animals.Add(new FarmYardAnimal {Name = secondAnimalName});}

IntegrationTesting

What is Integration Testing

•  Testing components working together •  No Mocking

•  Long running

• Never sacrifice repeatability for speed

• Large setup, multiple Asserts  

 Database Integration Testing[Test] public void Using_The_DTC_To_Rollback_Transactions(){using (new TransactionScope()){using (ISession session = _sessionFactory.OpenSession()){   var status = new GameStatus    {        ActivePlayer = "active",        CanSnap = true,        Giant = "giant",        IsFinished = true,        Jack = "jack"     };

session.SaveOrUpdate(status);Assert.IsTrue(status.Id > 0);}}

Database Integration Testing cont...[Test, Rollback]public void Using_MbUnit_To_Rollback_Transaction() {  using (ISession session = _sessionFactory.OpenSession()){   var status = new GameStatus    {        ActivePlayer = "active",        CanSnap = true,        Giant = "giant",        IsFinished = true,        Jack = "jack"     };

 session.SaveOrUpdate(status); Assert.IsTrue(status.Id > 0);}

Code Coverage - NCover•  Commercial & Free versions available •  Bundled as part of Testdriven.Net  •  Good indication of code requiring tests                                                             BUT •  High test coverage != Fully tested

NCover cont...

 

ProductionTesting

Deployment Verification Tests

Automated tests in production

Is the deployment ok?• Verify resources have been installed• Verify software has permission to resources

(file, databases, services, etc...)• Verify that manual software environment is

correct (Windows version etc)

Deployment Verification Tests

• DVT Hippocratic Oatho DO NO DAMAGE!o How much mess can you live with

Log changes?Test data in production?

• Not testing functionality that is done in lower environments

Deployment Verification Tests

 Steps• Create a mbUnit project specifically for DVT• Execute test runner console in production• Ensure that the Unit tests load the SAME

configuration files as the SUT• Ensure test runner is executed using the

same Windows credentials as the SUT

Deployment Verification Tests

Create a library of common tests... • DatabaseAssert library

oDatabaseExists();oStoredProcedureExists();

• FileServerAssert libraryoCanOpen();oCanDelete();

Monitoring and Alerting - HeartbeatsContinuous tests in production

• If a server is down, how long does it take to find out?oWithin 5 minutes or when the users

complain• Create a service that can be remotely

executed • Ensure it touches all the systems it depends

upon

Merry ChristmasThanks for listening 

   • http://www.fitnesse.org• http://www.mbunit.com/• http://ayende.com/projects/rhino-mocks.aspx  

  

Code @ www.pebblesteps.com

Back Story for Jack Plays Snap

Its almost Christmas... 

Midland Organic Foods are thinking about Easter • Temporary product for Easter called

Beanstalk Munchies• Organic biscuits coated in chocolate• Biscuits shaped like Farm Yard Animals

based on Jack and Beanstalk fairy tail• Golden Gooses Egg in the middle of the

box

The Pitch - VisionIncrease sales by creating Buzz...

• Client wants to create buzz around product launch

• Want a Web game that they can advertise on TV and in retail stores

• Ideas...  Puzzle game or Education game